This invention relates to a refrigeration cycle utilized for both of refrigeration system and air conditioning system which are equipped in a vehicle or a general building, and further relates to a refrigeration cycle utilized for air conditioning system, etc. which can air-condition front and/or rear seat spaces in the vehicle, or separated spaces in the building concurrently or selectively. More particularly, this invention relates to a refrigeration cycle control system for controlling above refrigeration cycles.
As disclosed in Japanese examined patent publication No. 63-33061, for instance, a refrigeration cycle conventionally has an expansion valve for refrigeration and an expansion valve for cooling which are connected to a compressor in series and connected each other in parallel, an evaporator for refrigeration connected to the expansion valve for refrigeration in series at the downstream of the refrigeration valve and an evaporator for cooling connected to the expansion valve for cooling in series at the downstream of the cooling valve and constructing parallel circuit with the cooling expansion valve to a circuit including the refrigeration expansion valve and evaporator. In the above refrigeration cycle, a solenoid valve is provided in the parallel circuit at the upstream of and in series of the cooling expansion valve. The cooling evaporator operates to cool while the solenoid valve is open. The solenoid valve is switched to be closed when only the refrigeration evaporator is switched to operate.
However, the refrigeration cycle has following drawbacks. First both evaporators are operated, and when the operation is switched to operate only the cooling evaporator, the solenoid valve is closed. At the same time vibration and/or noise arise around pipe line at the upstream side of the solenoid valve and the cooling evaporator due to water hammer phenomenon because liquid refrigerant flow in low compressibility at the upstream of the solenoid valve is suddenly stopped when the solenoid valve is closed.